The Satellite Centre at Surrey has 8 microsatellites
that orbit above the equator at 970 km above the Earth. They are equally
spaced and their 'footprints' overlap to ensure the whole Earth is covered.
Find out more about six of our missions...

Some satellites are in Low Earth Orbit (LEO) at a height of only about
700 km above the Earth's surface. They orbit over the pole once every
100 minutes approximately and can see a different segment of the Earth
as it spins beneath the satellite. All of the satellites are continuously
monitored by Mission Control at Surrey Space Centre as they pass over
head at 7.5 km/s. This makes sure each one is in the correct orbit and
attitude (orientation) and allows the scientists to download any data
the satellite has taken in its journey around the earth. Each pass lasts
only 10 - 20 minutes before the satellite is again out of reach.

Communications satellites such as those that transmit television signals,
are in geostationary orbit. They go round the equator once in 24 hours.
This is how they remain above the same spot on the Earth all the time.
These travel much more slowly than LEO satellites and are about 36000km
above the Earth's surface.

Orbit:
780 km circular orbit, 98 degree inclination

UoSAT-3 has far outlived its original design life of three years and
was 'retired' from active service in 1999. As the spacecraft is still
operational, engineers switched UoSAT-3's communications links from
digital store-and-forward communications to an FM voice transponder
mode for use by international amateur radio operators.

28th February 2001 Amateur radio operators helping with earthquake
relief operations in India, used small satellite built and launched
11 years ago as the primary link to the outside world after the earthquake
while many telephone services in the earthquake zone were out of action.

Another Bangalore radio amateur and a former UNESCO official, Chandru
Ramachandra, drove some 1700km to Bhuj carrying a medical team and 400kg
of equipment and supplies, setting up a satellite ground station to
establish a link between the earthquake site and Bangalore using UoSAT-3.